Can you tell me what is chronic sinusitis and is it serious?

Chronic inflammation: It is a chronic inflammation of the nasal and sinus cavities that results in recurrent sinus infections, nasal congestion, postnasal drip, sinus pain/pressure, cough and often nasal discharge. It can be caused by various things like allergies, smoking, bacteria, various fumes, etc. It is serious because it makes one miserable and can lead to more serious lung, eye and brain infections.

90 days: The definition of chronic sinusitis is documented sinus inflammation that lasts for 90 days or longer. This problem requires an ENT doctor. It may be serious but usually the patient with this problem has a poor quality of life. Complications of acute sinusitis, particularly in children, are more common and more serious.